摘要
The fundamental mechanism of the cracking formation was investigated for the as-cast GH4151 superalloy.By analyzing the characteristics of cracking,the cracking mechanism was determined to be the cold crack formed during the cooling process.And cold cracking is closely related to severe segregation,complex precipitates and uneven γ'phase distribution.During cooling process,cracks were generated around the precipitates due to their different linear shrinkage coefficients.The annealing treatment process controlling the residual stress,the size and morphology of γ'phase was proposed.The annealing treatment plays a role in reducing residual stress through decreasing the thermal gradient and controlling the size distribution of γ'phase to reduce the strain concentration around the precipitate phases.
研究GH4151铸态高温合金裂纹形成基本机理。通过对裂纹特征的分析,确定其开裂机理为冷却过程中形成的冷裂纹。冷裂纹的形成与严重的偏析、复杂的析出相和γ'相分布的不均匀性密切相关。冷却过程中,由于不同析出相线性收缩系数的不同,在析出相周围会产生裂纹。提出一种控制残余应力、γ'相大小和形态的退火工艺。退火处理发挥很大作用,通过降低温度梯度减小残余应力以及控制γ'相的尺寸分布,从而减少析出相周围的应变集中。
基金
Project(50974016)supported by the National Natural Science Foundation of China。
